Craniofacial dysmorphologies are some of the most common human birth defects and can be extremely variable in their severity and extent. Understanding, diagnosing and treating these dysmorphologies requires a detailed understanding of the normal genetic hierarchies, cell signaling and cellular interactions that drive the morphogenesis and integration of the multiple cell types within the craniofacial complex. Genetic and/or environmental perturbations that disrupt these normal processes can cause craniofacial dysmorphologies. Given that human craniofacial birth defects tend to be sporadic and non-syndromic, it is most likely that multifactorial perturbations are the most common cause of these defects. However, there are major gaps in our understanding of the normal processes in craniofacial development. Furthermore, we have very little understanding of how multifactorial interactions disrupt normal development. This R35 proposal will support the unique research program of Dr. Johann Eberhart?s lab. The signaling interactions mediating craniofacial morphogenesis are examined in the first program. The second program examines how craniofacial tissues integrate seamlessly with one another. The third program examines the environmental and gene-environment interactions that can disrupt craniofacial development. Dr. Eberhart is an extremely well trained and productive developmental biologist. He has been supported through various NIH-based mechanisms ever since he was an undergraduate student. He has authored 40 total publications, 28 since establishing his independent lab at UT Austin. He has established himself as a leader in the field of craniofacial development and has pioneering publications on muscle-tendon attachments, zebrafish palatal development and gene-environment interactions. Dr. Eberhart is routinely invited to present the work from his lab at national and international meetings. He is also regularly asked to provide scientific service, such as grant reviews and organizing/participating in scientific workshops. Dr. Eberhart is a tireless mentor. He not only ensures that his trainees research is top notch, but is also deeply engaged with their scientific careers. To date, every one of Dr. Eberhart?s trainees that have been eligible for fellowships have received at least one. Dr. Eberhart is also committed to increasing diversity in STEM fields and actively recruits promising young scientists from diverse backgrounds into the field.